The most difficult subject

The most difficult subject can be explained to the most slow-witted man if he has not formed any idea of them already; but the simplest thing cannot be made clear to the most intelligent man if he is firmly persuaded that he knows without a shadow of a doubt, what is laid before him.

— Leo Tolstoy, 1897, as quoted on the opening page of The Big Short by Michael Lewis, the book I was reading on the flight to Kuala Lumpur. Really good.